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 A367007 Number of distinct prime factors of n*2^n + 1. 4
 0, 1, 1, 1, 2, 2, 3, 3, 2, 2, 3, 2, 3, 2, 3, 3, 2, 3, 4, 4, 3, 2, 4, 4, 4, 4, 4, 4, 2, 3, 5, 5, 3, 2, 5, 2, 3, 3, 3, 3, 3, 4, 4, 5, 4, 4, 5, 5, 4, 2, 6, 3, 6, 3, 5, 4, 3, 5, 5, 4, 4, 7, 3, 3, 6, 5, 7, 4, 4, 5, 5, 5, 5, 5, 3, 5, 4, 4, 4, 6, 4, 4, 4, 5, 4, 6, 6 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS The numbers n*2^n+1 are called Cullen numbers. LINKS Amiram Eldar, Table of n, a(n) for n = 0..865 FORMULA a(n) = omega(n*2^n + 1) = A001221(A002064(n)). MATHEMATICA Table[PrimeNu[n*2^n + 1], {n, 0, 100}] (* Amiram Eldar, Jan 06 2024 *) PROG (PARI) a(n) = omega(n*2^n + 1); \\ Amiram Eldar, Jan 06 2024 CROSSREFS Cf. A002064, A001221, A367004, A367005, A367006. Sequence in context: A055092 A213202 A234972 * A130326 A059906 A349196 Adjacent sequences: A367004 A367005 A367006 * A367008 A367009 A367010 KEYWORD nonn AUTHOR Sean A. Irvine, Oct 31 2023 STATUS approved

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Last modified February 29 09:21 EST 2024. Contains 370418 sequences. (Running on oeis4.)